1. Field of the Invention
The present invention generally relates to display panel modules and a method for manufacturing the same and more particularly relates to improvement in plasma display modules having functional films directly bonded to front faces thereof. The display panel modules are main units of flat display devices and include a display panel, a functional film and a drive circuit board each. The display devices each include a display panel module and a casing for housing the same.
2. Description of the Related Art
The display panels are devices termed flat panel displays such as plasma display panels, liquid crystal panels, organic electroluminescence displays or field emission displays.
A translucent functional film is bonded to a front face of a display panel in order to improve performance of a display device for displaying images using the display panel. The functional film has at least a function of preventing reflection of external light. In the case of a plasma display panel, other functions realized by using the functional film include display color correction, electromagnetic wave shielding and near infrared ray shielding. For example, a functional film described in Japanese unexamined patent publication No. 2004-206076 has an anti-reflection layer, a color filter layer and an electromagnetic wave shielding layer and is bonded to a front face of a plasma display panel.
A step of bonding a functional film precedes a step of assembling a display device, i.e., of housing a display panel in a casing. More specifically, in manufacturing a display device, a display panel module provided with a functional film and a drive circuit board is manufactured first, and then, the display panel module is incorporated into a casing.
According to conventional manufacturing methods of display panel modules, a functional film is bonded to a front face of a display panel prior to attaching a drive circuit board to the display panel. This manufacturing procedure is suitable when a functional film is bonded under a clean environment such as a clean room. Since relatively much dust adheres to a drive circuit board, it is undesirable to carry the drive circuit board to a clean room. When a functional film is bonded to a display panel after attachment of a drive circuit board, much dust (many foreign matters) may be present between the functional film and the display panel.
According to conventional methods, when some defects of a display panel are found by a lighting test conducted after manufacturing a display panel module, it is necessary to detach a functional film from the defective display panel, then to discard the functional film. Alternatively, it is necessary to perform a difficult reproduction process that involves removal of surface foreign matters and attachment of a mold release film, then to bond the functional film thus reproduced to another display panel. This lowers productivity, causing a problem of increase in production costs of display panel modules. In particular, damage of a functional film at the time of detachment thereof further increases production costs.